Process for concentrating beryllium minerals



United States Patent 3,112,260 PROCESS FOR CONCENTRATING BERYLLIUM MINERALS Charles C. Cook, Lakeland, Fla., assignor to Vitro Corporation of America, New York, N.Y. No Drawing. Filed Feb. 2, 1961, Ser- No. 86,572. 2 Claims. (Cl. 209-12) This invention relates to a method of treating beryllium ores.

Beryllium is a valuable metal having a wide variety of uses such as in the preparation of beryllium alloys. At the present time beryl (3BeO'Al O -6SiO is the only commercial source of beryllium, the usual grade of beryl containing from about 8 to 10% beryllium oxide.

Bertrandite (4BeO-2SiO -H O) is a beryllium-bearing mineral which may contain a maximum of about 42% beryllium oxide. No process presently exists for recovering bertrandite from any of the ores in which it occurs. Certain ores are known which contain the minerals beryl and bertrandite in admixture and it would be desirable to concentrate and separate mixtures of these minerals when they do occur together.

It is known that beryl may be subjected to a flotation procedure in order to concentrate the mineral and aid the eventual recovery of beryllium. Flotation treatment of the usual grade of beryl containing about 1.0% beryllium oxide produces a concentrate containing about 97.4% beryl with a recovery of 82%.

Accordingly, it is an object of this invention to provide a method for the recovery of bertrandite from ores containing the mineral.

Another object of this invention is to provide a method of concentrating and separating a mixture of beryl and bertrandite.

Other objects and advantages of the invention will be apparent from the following description.

It has now been found that bertrandite and mixtures of bertrandite and beryl may be separated from their ores by a novel flotation procedure.

The first step in the recovery of bertrandite is to crush the mineral-bearing ore to a particle size of about mesh in order to free the mineral particles from one another and from the bulk of the ore. The ground mate rial is then subjected to a desliming operation which temoves a large proportion of the fines. The slimes usually consist of silicates such as talc or clay colloidally suspended in the ore pulp. If not removed, they are susceptible to coating by collectors with the resultant excessive consumption of this reagent. The slime, if not removed, also may tend to contaminate the concentrates, reduce the recovery of the minerals and result in overfrothing during the actual flotation. Desliming is generally accomplished by agitating an aqueous slurry of the ground ore, allowing the mixture to settle for a brief period of time and then decanting the free water and suspended slime material. This procedure may be repeated a number of times.

The deslimed ore pulp is treated by flotation to remove much of the mica present. Conditioning is carried out for at least 5 minutes at a pulp density of 60-70% solids 3,112,260 Patented Nov. 26, 1963 "ice with about 4 lbs. of sulfuric acid per ton of material treated, about 1 lb. of a long chain fatty amine salt, about 0.5 lb. of kerosene and about 0.1 lb. of a frothing agent such as pine oil or a long chain alcohol such as methylamyl alcohol. Any cationic long chain fatty amine salt can be used as the collector. These materials are Wellknown collectors and, as such, do not form the basis for the present invention. A tallow amine acetate salt sold under the trade designation Armac T has been utilized successfully as the collecting agent. This particular amine is derived from the following tallow fatty acids:

Percent (a) Hex-adecyl 30 (b) Octadecyl 25 (c) Octadecenyl i 45 The kerosene apparently functions as an auxiliary collector. Conditioning is effected with a Light nin impeller-type mixer operated at a speed suflicient to keep the pulp completely mobile.

The tailing from the H 50 flotation step, being substantially free of mica, is then subjected to a cleaner flotation stage or refioat. Here, conditioning for about 2 minutes with 0.5 lb. of a hydrocarbon oil such as mineral oil for each ton of feed acts to depress the bertrandite and also any beryl which may be present. This effect is obtained without the addition of other reagents. The use of an oil in the first flotation step does not give this result and the effect in the refloat is therefore quite surprising. Squibbs mineral oil may be utilized as the reagent althrough hydrocarbon oils of the same type including fuel oil and motor oil may be used.

The bertrandite concentrate is recovered from the tailing of this refiotation step and may be separated from any beryl present by magnetic means, the bertrandite being recovered in the magnetic fraction.

Example.An ore sample obtained from the Lake George, Colorado, area and containing beryl, bertrandite, mica, quartz and other silicates was fed through a jaw crusher and ground to a particle size of about 30 mesh. The crushed ore was thereupon deslimed by washing with water and decanting the slime. The desliming was accomplished in 3 stages. Water was added at the rate of about 40 lbs. per 100 lbs. of ore and after being allowed to settle for 2 minutes after agitation, the free water and slime was decanted. This procedure was repeated twice. The deslimed ore was then conditioned for 5 minutes at 60% pulp density with 4 lbs. per ton of sample of sulfuric acid, and floated in a standard float cell by the addition of 1.0 lb. of Arrnac T, 0.5 lb. of kerosene and 4 drops per ton of pine oil. The tailing from this flotation stage was recovered and refioated by conditioning for 2 minutes with 0.5 lb. per ton of pulp of Squibbs mineral oil. The tailing from this refiotation step contained about 8-10% beryllium oxide which represented a -90% recovery of beryllium oxide. The beryl and bertrandite present in the sink were separated from one another by the use of a magnetic separator, the bertrandite being recovered in the magnetic fraction.

The following diagram represents a fiow-sheet of the It will be understood that the described embodiment novel process: of the invention is illustrative only and that modifications Bmrammc will occur to those skilled in the art. Therefore, the invention is not to be limited to the specific example de- 5 scribed herein but is to be defined by the appended Crush to liberation (30 mesh) lai s, 1 .Ai I claim:

1. The method of recovering bertrandite from its ores which comprises floating the deslimed ore pulp with about 4 lbs. of sulfuric acid per ton of feed, about 1 lb. Couditionat least51ninutesatGG-TDQEsolids of a Cationic long Chain fatty amine Salt, abOut O-S of kerosene, and about 0.1 lb. of. a frothing agent, refioating the tailing from said flotation stage by the addi- Amine'kcmsmc film P tion of about 0.5 lb. of a mineral oil per ton of feed and recovering bertrandite from the tailing of said refioat stage.

2. A method in accordance with claim 1 wherein the Fawn bertrandite is recovered from the tailing of said refioat by magnetic means.

Dcsliine if necessary 0.5 ill/i011 of mineral 011 11 References Cited in the file of this patent UNITED STATES PATENTS Float Failings 2,395,475 G bbs Feb. 26, 1946 BOO (or better) 2666587 Runke 7t]-t)l),lb BcO recovery OTHER REFERENCES Magnetic p r r Bureau of Mines Publication RI4166, January 1948. Deco 'Frefoil, pages 15 and 16, September-October i 1958, Flowsheet Study Bulletion No. M7F62, Beryl um rilrltlite Beryl Ore Flotation. magnetic fraction non-magnetic fraction 

1. THE METHOD OF RECOVERING BERTRANDITE FROM ITS ORES WHICH COMPRISES FLOATING THE DESLIMED ORE PULP WITH ABOUT 4 LBS. OF SULFURIC ACID PER TON OF FEED, ABOUT 1 LB. OF A CATIONIC LONG CHAIN FATTY AMINE SALT, ABOUT 0.5 LB. OF KEROSENE, AND ABOUT 0.1 LB. OF A FROTHING AGENT, REFLOATING THE TAILING FROM SAID FLOTATION STAGE BY THE ADDITION OF ABOUT 0.5 LB. OF A MINERAL OIL PER TON OF FEED AND RECOVERING BERTRANDITE FROM THE TAILING OF SAID REFLOAT STAGE. 